An experimental grammar fuzzer in Haskell using QuickCheck
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QuickFuzz, a tool written in Haskell designed for testing un- expected inputs of common file formats on third-party software, taking advantage of off-the-shelf, well known fuzzers. Unlike other generational fuzzers, QuickFuzz does not require to write specifications for the file formats in question since it relies on existing file-format-handling libraries available on the Haskell code repository. There is more information in its website.



In this example, we uncover a null pointer dereference in gif2webp from libwebp 0.5:

$ QuickFuzz gentest gif "./gif2webp @@ -o /dev/null" -l 1 -u 10 -f radamsa
Test case number 4481 has failed. 
Moving to outdir/QuickFuzz.68419739009.4481.3692945303624111961.1.gif

We found a crash. We can inspect it manually to verify it is a null pointer issue:

$ ./gif2webp outdir/QuickFuzz.68419739009.4481.3692945303624111961.1.gif
==10953== ERROR: AddressSanitizer: SEGV on unknown address 0x000000000000 
(pc 0x000000403ff9 sp 0x7fffffffd6e0 bp 0x7fffffffded0 T0)
AddressSanitizer can not provide additional info.
#0 0x403ff8 (examples/gif2webp+0x403ff8)
#1 0x7ffff437af44 (/lib/x86_64-linux-gnu/
#2 0x401b18 (examples/gif2webp+0x401b18)
==10953== ABORTING

Finally, we can shrink the crashing input to obtain a smaller file:

$ QuickFuzz gentest gif "./gif2webp @@ -o /dev/null" -l 1 -s 3692945303624111961 -f radamsa -r
Test case number 1 has failed. 
Moving to outdir/QuickFuzz.68997856397.1.3692945303624111961.1.gif
Shrinking over bytes has begun...
Testing shrink of size 48
Testing shrink of size 47
Testing shrink of size 15
Shrinking finished
Reduced from 48 bytes to 16 bytes
After executing 554 shrinks with 33 failing shrinks. 
Saving to outdir/QuickFuzz.68997856397.1.3692945303624111961.1.gif.reduced


We support Stack to compile and install QuickFuzz. Before starting with it, make sure you have libgmp-dev installed otherwise ghc will fail to compile. Also, zlib.h is required to compile QuickFuzz (some packages require it). For instance, in Ubuntu/Debian:

# apt-get install zlib1g-dev libgmp-dev libtinfo-dev

After installing stack, you should:

$ git clone --depth 1
$ cd QuickFuzz
$ stack setup

Because QuickFuzz generates a lot of dependencies that may not be necessary to test an specific category of files, we modularized the project with different activation flags. Currently we have 7 flags:

Flag Supported formats
image svg, png, gif, tiff, jpeg
arch tar, zip
doc html, css, pdf, ps, eps, xml
code c, js, py, go, lua, evm
media wav
net http
pki asn1, crl, x509
bnfc cf, grammer format

For instance, to compile only with image generation (Bmp, Gif, Png, Ico, ..):

$ stack install --flag QuickFuzz:image

Because of a Stack issue, you must install alex and happy manually before enabling the code flag:

$ stack install alex happy

Cabal Installation

Direct cabal installation is not recommended nor supported.



  • Franco Costantini
  • Lucas Salvatore

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